“Extreme weather”, such as a local downpour that may be called torrential rain, is a weather phenomenon that causes serious damage to human and material in an extremely limited region. The damage becomes more serious as a population density increases, and in particular, in an urban area on which human activities are concentrated, the damage may become extremely conspicuous.
Also, an unprecedented aging society is currently progressing rapidly in Japan, and population concentration is progressing on cities where life is convenient. Moreover, a rise in an urbanization rate is posing a problem worldwide as well, and it is said that the urbanization rate, which is 50% as of 2013, is likely to reach 70% in 2050.
Meanwhile, prediction accuracy of extreme weather in a limited region is only about several percent under present circumstances, and improvement in the prediction accuracy is highly desired.
Therefore, improvement in numerical weather forecast is promoted for purposes of finely predicting weather information in a small region (for example, refer to Patent Literature 1).